This invention relates to an apparatus used for measuring the physical strength of a person. More specifically, the invention relates to an apparatus which dynamically measures the instantaneous power output of a single leg muscle, via the leg extending power of the subject. The present invention also monitors forms of motion by measuring the instantaneous power of a multi-articular motion such as a vertical jump.
The following problems have been noted with respect to conventional physical strength tests such as a vertical jump test, a reciprocal jump test and a dorsal muscle test.
(1) It is difficult to link the test results with a synthetic appraisal, since various functions are appraised separately.
(2) Appraisal standards are ambiguous. For example, with respect to a vertical jump, the appraisal standard is the height to which one can jump; however, this is an index of the performance, and is an indirect and substitutive appraisal of the physical strength.
(3) There is no standardized scientific proof, which relates an index of performance (i.e. a persons vertical jump) to physical strength.
(4) Often the test subject must perform unusual movements with a large load, which often result in injury. Recently, an increased interest in physical strength has generated a demand for a method and apparatus, which measures physical strength easily, safely and accurately. Also, a study has been made, which creates an index of the physical strength based on the power theory.
In the power theory, physical strength is measured as the capacity of the energy (integrating value of the power), or the power is measured as an index. Forms of power development are classified according to energy developing mechanisms (i.e. specific muscles) in a living body. Within each form of development, the upper limit value of power is measured while monitoring the corresponding energy developing mechanism (muscle). This measured upper limit is used as an index of physical strength in the corresponding energy developing mechanism.
Specifically, the measurements are carried out in the following manner:
(a) Oxygen-present energy mechanism
Duration: Infinite
Appraisal of upper limit power: Power available at 75% of the maximum heat rate, etc.
Main factor for energy generation: Oxygen
(b) Lactic acid-type anoxia energy mechanism
Duration: About 30 seconds
Appraisal of upper limit power: Average power, critical power, etc.
Main factor for energy generation: Glycogen
(c) Non-lactic acid-type anoxia energy mechanism
Duration: About 7 seconds
Appraisal of upper limit power: The optimum value determined by speed and developing force of the peak power around approximately 5 to 6 seconds.
Main factor for energy generation: ATP-CP type chemical energy.
In connection with the above energy mechanisms (a) and (c), a measurement apparatus utilizing a bicycle ergometer has been proposed by the Applicant of the present invention (Japanese Patent Publication No. 42694/89), and there are known "AEROBIKE" and "POWERMAX" (both of which are registered and pending trademarks of Konbi Corporation; the former is Japanese Trademark Registration No. 1840771, and the latter is Japanese Trademark Publication No. 42348/86) to which the above techniques are applied.
The energy mechanism of example (b) can be carried out with a Wingate test. An apparatus for measuring an instantaneous power of the subject utilizes a bicycle ergometer, since the pedaling motion is analogous to a usual running motion and is rhythmic. The power can be produced efficiently, with less injuries resulting.
On the other hand, with respect to a continuous leg muscle power exercise or other similar multi-articular exercise, the instantaneous power of a single leg muscle is also an important factor, for example, when hastily avoiding an obstacle in daily life. An apparatus is known, which measures the instantaneous power of a single developing leg muscle, for example, as disclosed in Japanese Laid-Open (Kokai) Utility Model Application No. 18103/88. In this application, a leg's extension power is received by a hydraulic or pneumatic cylinder, and the physical strength of the subject is measured according to data from the cylinder.
However, in the above leg extension measuring apparatus, the adjustment of the cylinder is very difficult. In addition, since the load varies in accordance with the speed, it is difficult to accurately measure the instantaneous power.
Further, when using the hydraulic cylinder, the response time of the hydraulic pressure is slow, which prevents an accurate measurement.